Microorganisms and enzymes are able to catalyze a broad spectrum of organic reactions under mild conditions, and with selectivities and stereochemical specificities not easily achievable using traditional chemical approaches. The overall objectives of this research are: to gain an insight into the kinetic parameters that govern enzymic enantioselectivity; to develop quantitative expressions that will allow prediction of the enatiomeric excess of the product fraction; to develop strategy for enhancing optical purity of the chiral species during biochemical asymmetric catalysis; and to demonstrate great opportunities that the uses of biochemical systems present to the organic chemist, particularly for asymmetric synthesis. Currently, the oxido-reductases of fermenting yeast and hydrolytic enzymes are being exploited to achieve the preparations of a broad spectrum of useful chiral synthons via enantiomeric and prochiral stereospecificity distinctions. These synthons are useful for the preparation of amino acids, vitamins, leukotriene B4, and microbial autoregulators.